Electric switch and the like



1939- A. M. DRAVlNG E AL 2,159,369

ELECTRIC SWITCH AND THE LIKE Filed Feb. 27, 1931 3 Shets-Sheet l May 23, 1939. I A. M. DRAVING El AL 2,159,369

ELECTRIC SWITCH AND THE LIKE Filed Feb 27, 1931 s Sheets-Sheet 2 y 23, 1939- A. M. DRAVING ET AL 2,159,369

ELECTRIC SWITCH AND THE LIKE] Filed Feb. 27, 1931 3 Sheets-Sheet 3 Our invention relates to electrical switches, Figure 2 is a section taken upon the line 2-4 of either separately or in combination with poten- Figure 1.

tiometers, volume controls, tone controls or re- Figure 3 is a detached perspective view of the sistances. principal parts of the switch of Figures 1 and 2.

A purpose of our invention is to throw a switch Figure 4 is a perspective view of a somewhat 5 Patented May 23, 1939- UNlTED -STATES PATENT OFFICE ELECTRIC swrron AND THE LIKE.

Arthur M. Draving and William Irwin Ingham,

Philadelphia, Pa., assignors, by mesne assignments, to Chicago Telephone Supply Company, Elkhart, Ind., a corporation of Indiana Application February 27, 1931, Serial No; 518,836

4 Claims. (01. 201-55) by means of a tripping lever, preferably pivoted different form of our invention, in which the on the switch blade pivot, and to hold the switch switch is located in the same casing as a potenblade in open or closed position by pressure from tiometer, volume control or tone control and is the movable end of the switch blade against the thrown by moving the dial.

tripping lever in one of its limiting positions. Figure 5 is a section of the form of Figure 4,

A further purpose .is to provide an extension taken-upon the line 5-5 of Figure 6. from a tripping lever, so that the switch may be Figure 6 is a section upon the line 6-6 of Figthrown by engaging the extension. ure 5.

A further purpose is to shape a tripping lever Figure 7 is a section corresponding to Figure 6, extension so that a projection moving over a prebut showing the switch in its opposite position. determined path can engage the extension in one Figure 8 is a section upon the line 88 of Figposition, and, after throwing the switch, move ure 5. free of the extension. Figure 9 is a fragmentary section upon the line A further purpose is to limit the movement of 9 o F u e a tripping leverand of its switch blade by stops, Figure 10 shows a variation in a section taken preferably using a single stop to engage the tripupon the line I0-l0 of Figure 11. ping lever in both of its extreme positions and to Figure 11 is a section of Figu 10 p the line engage the switch blade in open position. I I.

A further purpose is to mount a switch to be Figure 2 i a vi w r p n in to Fi ur operated byapotentiometer, volume control, tone Showing e SWitGh in its closed Position and control or resistance dial within the control or omitting some Of the Contacts extending b y other casing, and to throwthe switch by a projecthe c tion from the movable contact of the device, pref- Figure 13 is a section'uPO t e li e 3-l3 0f erably insulating the projection from the contact. Figure A further purpose is to place within the casing Figure 14 is a Section Of Figure 11 p the of a potentiometer, volume control, tone control line 14-44. or other variable resistance, a switch operated by In, e gs e a s refer to like the movable contact, and to open and close the p switch in a plane parallel to the plane of move- Numerous Switches upon the market W P- ment of th contact, crate by motion transmitted through turning a A further purpose is to trip a full stroke switch Shaft, but relatively few Switches y be thrown by one portion of the movement of a projection by Substantially translatory movement of a froma resistance-varying contact, desirably hav- Switch Operating projection and of these, even ing the projection move free of the tripping fewer embody the fun stroke featuremechanism in other positions. I In switches intended for opening and closing A further purpose is to locate a switch Within electric lighting circuits, radio circuits and the the annular Space inside resistance c011 and to like, provided suitable electrical and mechanical operate the Switch by turning the dial by which characteristics arepresent, cheapness is the prime the resistance is Varied. grslsenltlial. Tlfie elinizngatzgnto1;3 a. single past 0;

Further purposes will appear in the specificae C ange 0 a par 0 a 1 may e-pro use v by a cheaper process, may make it possible to sell H011 and m a switch which could not otherwise be placed min the drawings we illustrate a few only of the upon the market. mer0us Vana'QmnS m 'i our mventlon We have invented a switch which meets the mlght be embodfid, Chooslng the forms shown electrical and mechanical demands exceptionally irom the standpoints of ease in construction, satwell, and at the same time is extremely simple e y ep and Convememi illustration 0f in construction. Aside from the switch blade and the principles involved. its pivot, only three parts are required in our pre- Figure 1 is a rear elevation of a swit h embodyferred construction to perform both the tripping ing our invention. and full stroke functions. Of these, one is a spring and the others are extremely simple stampings. I

Essentially this embodiment of our invention involves the use of a tripping lever to throw the 5 switch blade through a toggle of which the tripping lever forms one element.

In the drawings we illustrate our switch separately and also embodied in two slightly variant forms of volume control. We will first describe other side of its neutral position, so that the tripping lever portion 40 engages the stop 38, and the plunger 27 swings about the walls of the opening 32 in the switch blade tab 33 as a pivot, while the Walls of the notch 26 in the swinging r end of the plunger 21 maintain their engagement with the walls of the notch 25 in the tripping lever 26.

Shifting of the position of the toggle com- To open the switch, the tripping lever 24 is moved to its opposite limiting position in any suitable manner, as by contact of the tripping projection 35 against the edge 36 of the tripping lever notch 34. This swings the toggle to the the other of the clips 81 and' 68 pressed up from the body of the casing. In the form of Figures 1 to 3, the spindle 58 performs no other function than that of throwing the switch, so that therethe construction of the switch proper, as seen presses the spring 3|, so that as soon as the tog- 10 in Figures 1, 2, 3, 5, 6, '7, 9, 11, 12 and 14. gle passes its neutral position, the switch blade The switch contacts comprise a stud 20 and a is snapped to open position under the action of spring strip 2|, which are connected together by the spring, simultaneously with or even before a switch blade 22 when the switch is in closed the arrival of the tripping lever against the stop.

position as seen in Figures 7 and 12. The switch The switch blade 22 comes to rest when the por- 15 blade 22 is pivoted at 23, and moves to open position 4| of the switch blade strikes the stop 38. tion as shown in Figures 6 and 11. The details of the switch housing and of the On a pivot line Within the edge of the switch means for operating the tripping projection are blade and preferably on the switch blade pivot 23 immaterial to the broad aspects of our invention.

as shown, we place a tripping lever 24, which is However, certain features of the housing and of 20 free to turn with respect to the switch blade 22. the operation of the tripping projection cooper One end of the tripping lever 24 is notched at ate very desirably with the switch of our inven- 25 to engage a cooperating notch 26 in a pluntion, particularly because the plane of movement l v of the switch blade in opening and closing is the 25 A recess 28 in the plunger 2! permits the same as the plane of movement of the tripping 25 plunger to fit firmly into the tripping lever notch projection, so that the switch assembly may be 25 without engaging the opposite walls of the made very compact. tch- In Figures 1 to 3 we show our switch in a cas- The plunger 21 is reduced in width at 29, forming intended to hold the switch alone. The parts 30 mg S o s 30 a st W ich a Spring 3| surof the switch proper, as previously described, are 30 rounding the reduced portion 29 of the plunger, is mounted upon a base 42 of insulating material. held. The other end of the plunger passes The stud 20 passes through the insulation and is through an opening 32 in a tab 33 turned out riveted to a contact 43 on the back. The switch perpendicularly from the movable end of the spring contact 2| is secured by a rivet 44 to a Switch blade The tab 33 holds e Sp contact 45. From both of the contacts, 43 and 35 While the p ger is free to move through the 45, ears 46 have been bent down and extended tab. through the insulation to prevent turning of the The pp ve 24 s ed at ODDO- contacts 43 and 45. An opening 4'! in'the spring Site o e no h 5. r n m nt of a trip- Contact 2| admits the end of an car 46, to preping projection 35. The edges 36 and 31 of the t th Cont t 2| from turning. 40 notch 34 are preferably not y a S0 t at Openings 48 and notches 49 in the contacts the pp Prejeetion ay ove ut Of the 43 and faciltate, attachment of wires to the n tch n One d contacts. The stop 38 is the head of a rivet pass- A single stop 38 serves to limit the movement ing through the base 42. The switch blade pivot 45 of he tr pp ve 24 in both p and closed 23 is also desirably a rivet, on which a washer to 45 p s tio s a d 0 th Switch blade 22 in p P is placed to provide a smooth bearing for the tion. When the switch is closed, the shoulder itoh blade.

0f t pp v engages t p 33 as The switch is enclosed within a casing 5| s n i u s d In p position of flanged outwardly at 52 to hold the insulating the S the portio 40 0f the pp level switch base and peened at 53 to prevent removal engages the stop, and the portion 4| of the switch of th base, blade 22 al o engages the 1 b the a e- The casing is adapted to be supported from a ments are upon different portions of the stop as panel by tightening t upon a bushing 54 n in Figures 6 and 9 t t the resultant against a lock nut 55. The bushing is reduced in 55 lateral pressure against the stop is not excessive. d te at, 56 where it passes through an open- 65 The operation cLthe switch embodies the fulling in the casing 5|, and turned over at 51 to stroke principle. Considering the switch in unite t bushing t th casing, closed posit on as Shown n Figures 7 and 12, the Through the interior of the bushing passes a switch blade 22 is resiliently pressed against thespindle 58 which is coined at 5 at one end to 60 Switch contacts 20 and by sprmg 3L The receive an arm 60, desirably of insulating mate- 60 spring 3| acts at one end against the movable rial having a firingular opening BI and a stop end of the switch blade 22 and at the other end, 62 having an Opening 63 The so and the through the plunger 21, against the tripping stop 62 are secured to the spindle by riveting the lever 24 and ultimately against the stop 38.

65 It will be evident that the plunger 21 and the end the the arm 65 tripping lever 24 form a toggle, from which the P Secured a swltch pi g prolection 35 by switch blade is resiliently pressed into closed posillvetlng at 54 and by extending an ear through tion. the arm 60.

The switch is shown in open position in Figures The stop 62 carries a segment 66, which moves a 11 v between limiting positions in contact with one or 70 jection 35' move out of the slot 34 in the tripping lever 24.

To prevent inward slipping of the spindle 58 we provide a suitable collar 69 on the spindle at the outer end of the bushing 54, preferably making the collar a C washer contracted into a slot in the spindle.

In Figures 4 to 14 we illustrate embodiments of our switch in other apparatus to which it is particularly well suited. 4

The device illustrated might serve in any of the capacities suggested, namely, as a potentiomete'r, volume control, tone control or other variable resistance.

The greatest prospective utility is in volume controls and tone controls; but all are variable resistances and we have therefore called the device by that name.

In designing radio panels it is'highly desir-- able to have as few knobs and dials as possible.

The initial movement of the variable resistance dial commonly carries the contact over an insulating strip before the resistance winding is reached, and therefore is not directly effective in changing the resistance; It has been proposed to connect the variable resistance contact to a switch, desirably the main circuit switch of the set, so that the switch will be closed by this initial Variable resistance dial movement, and, when turning the variable resistance dial back to its initial position, so thatthe switch will be opened.

In' this way the extra knob ordinarily necessary for control of a switch is eliminated. The

connection in the past has been made from the variable resistance through a system of levers to a separate switch unit usually supported upon the back of the variable resistance casing.

By our-invention we are able to mount the switch within the variable resistance casing r proper, where the operating connection between the variable resistance contact and the switch may consist simply of a projection from the variable resistance contact. The operating projection is made to engage and throw the switch at one position of the contact and to travel free from the switch in the other positions.

In orderto avoid possible short-circuiting of the switch or the variable resistance, we insulate the tripping projection from the variable resistance contact in all positions. In the drawings we intend the illustration of the variable resistance shown by us to be essentially diagrammatic, since our invention is applicable 'to any variable resistance having a moving contact maker, whether'the moving body is the resistor or a contact sliding along the resistor.

In Figures 4 to 9, the casing 10, desirably made of metal, is formed in two parts, consisting of a front 1| and a rear 12 joined by flanging at 13 and peening at 14.

Within'the front part 1| of the casing we show a resistance winding 15 upon a form 16 and annularly surrounding an insulating disc 11. To prevent contact between the resistancewinding 15 and the casing, an insulating sheet 18 covers the inside of the frontcasing face.

The movable contact of the variable resistance consists of a spring metal clip 19 mported by annular arms 88 from a central disc 8| secured upon the variable resistance spindle 58. Cut from the central disc, a brush 82 wipes over the face of a disc 83 integral with a contact 84 extending through an insulating sheet 85 covering an opening 86 in the casing. The disc 83 has an ear 81 turned down and held in an opening 88 in the insulating disc 11. An ear 89 punched up from the casing front 1| also enters the opening 88. The ears assist in centering the respective parts.

Connection is made to the ends of the resistance winding 15 by contacts 90'and 9| bent into recesses 92 in the disc 11 and secured by screws 93. Where the winding is used as an ordinary rheostat, the contact 84 and one only of the contacts 98 and 9| will be employed, but where the winding is used as a potentiometer, the three contacts will all be used.

The construction of the bushing, spindle and stop mechanism is substantially the same as that shown in Figures 1 to 3, except in a few features as noted. The narrow portion 56 of the bushing extends through the insulating disc 11 and the contact disc'83 and is turned down at 51. A clip 61 is bent up from the contact disc 83 to engage the segment 66 of the stop 62 secured to the coined end of the spindle, and limit movement of the movable contact 19.1 The single clip 61 engages the stop in both limiting positions.

As seen in Figure 5, the spindle 58 extends through a panel 94 and carries a dial 95 which covers a nut 96 holding the variable resistance to the panel.

Thus far we have described what is essentially a conventional variable resistance. On the back casing portion 12 we mount a switch similar to that shown in Figures 1 to 3. Attachment of the switch base 42 to the casing isqdesirably made by rivets 91 as shown.

On the movable variable resistance contact 8| we secure in any suitable manner, as by rivets 98, an insulating piece 99 to the outer end of which the tripping projection 35 is fastened. As an additional protection against failure of elec- ,trical insulation between the variable resistance and the switch, we secure an insulating partition 100 to the base of the tripping projection 35.

When the movable contact 19 is in its limiting position at the end of the resistance winding connected to the contact 90, as shown in Figure 8, the tripping projection 35, opposite to the movable contact 19, is in the position shown in Figure 6, with the switch open. The spindle 58, contact 19 and tripping projection 35 cannot travel further counter-clockwise (as seen from the front) because of the spindle stop 62 and also because of the switch stop 38. Movement of the spindle 58 clockwise is however possible, and the first part of the clockwise stroke is effective to throw the switch from the open position as shown in Figure 6 to the closed switch position as shown in Figure '7. Further clockwise movement of the spindle 58 disengages the tripping projection 35 from the slot 34 of the tripping lever 24. The trip-ping projection 35 is seen in Figure '7 just after (leaving the slot 34. J

Further clockwise travel of the spindle 58 carries the movable contact 19 over the variable resistance winding 15, varying the resistance connected between the respective contacts 90, 84 and 9| in the usual manner.

Reversal of the direction of turning of the spindle first carries the movable contact 19 over the resistance winding 15, and finally causes the tripping projection 35 to engage the tripping lever 24 and open the switch.

Thus the initial and final ranges of movement of the variable resistance are employed to close and open a switch, which will ordinarily be the -main circuit switch in a radio set.

In Figures 10 to 14 we illustrate a somewhat different form of composite variable resistance and switch, in which the switch is located within the annular space inside the variable resistance, thus minimizing the space requirement and permitting closer connection between the variable resistance spindle and the switch.

The variable resistance in this form is essentially the same as that illustrated in Figures 4-9 except for variations in detail. The casing I0 is formed in two parts, of which the front portion II is metallic and the rear portion 12 is molded from suitable insulating material. The front portion II has been annularly flanged at l0I to fit within an annular depression I02 in the molded rear casing portion I2. At points I03 part of the outer edge of the metal casing portion II has been cut away to allow the casing to clear projections I04 extending from the walls of the depression I 02 and to permit the front casing portion II to be held in position by turning it with. respect to the rear casing portion I2.

The terminal 84' lies on the outside of the front casing portion 'II' and extends through the terminal notch 84 in the rear casing portion,"|2'. The notch 84 prevents turning of the front casing portion II with respect to the rear portion 12. The terminal 84' is united to the casing portion II by turning down the end 51 of the bushing 54. A projection 61, punched up from the front casing portion II, engages the movable stop 62 as in the other forms. An ear I05, turned down from the terminal 84, passes through the opening in the front casing portion 'II' formed by punching out the projection 61, to assist in centering the terminal.

The method of attachment of the movable stop 62 and of the movable contact I9 to the spindle 58 is identical with that used in the other forms. In Figure 13 we illustrate notches I06 in the movable contact disc to assist in connecting together a plurality of contacts for operation by a single spindle, where that is desired.

The resistance winding 15 and the form I6 differ somewhat from that shown in Figures 4 to 9, as the winding has been made wider to fit into a depression I0'I formed by an annular ridge I08 in the base of the molded casing I0. Connection to the ends of the resistance winding is provided by contacts and SI secured to the winding by screws 93', extending through the casing.

The switch has been mounted on a base 42' secured to the casing by rivets I09, and rested on the inner edge of the ridge I08. Leads H0, extend from the switch contacts 43 and 45 to contacts III and H2 secured to the rear of the casing I0 by rivets II3.

It will of course be evident that the space between the switch base 42 and the rear of the casing portion I2 may be used as desired, for example to hold a fixed resistor.

The structure just described is particularly desirable because space radially within variable desistance windings which otherwise would not be advantageously used, is employed to hold the switch. This is made possible because the switch opens and closes in a plane parallel to the plane of movement of the movable contact.

It will be evident, that, besides providing a distinctly useful switch, we provide a switch which is particularly well suited for embodiment in a variable resistance, because it may be thrown by a projection from the movable contact during a part only of the movable contact travel.

While we show a form of switch in which both contacts are touched by the switch in closed position only, it will of course be apparent that connection could be made permanently to the switch blade, as for example at its pivot, thus removing the necessity for one of the switch contacts shown. The number of contacts used is not vital to the broad aspects of our invention.

In view of our invention and disclosure variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of our invention without copying the structure shown, and we, therefore, claim all such in so far as they fall within the reasonable spirit and scope of our invention.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. In a composite potentiometer, volume control, tone control or rheostat with a switch, a casing, a susbtantially cylindrical resistance strip within the casing, a contact touching the strip and movable with respect to it, a switch within the casing and the strip and connection between the contact and the switch adapted to throw the switch in one position of the contact.

2. ha composite potentiometer, volume control, tone control or rheostat with a switch, a casing, a resistance strip within the casing conforming generally to the inner contour of the casing, a. contact touching the strip and movable with respect to it, a. projection from the contact, and a full stroke switch within the casing and the strip having tripping mechanism adapted to be engaged and thrown by the projection in one position of the contact.

3. In a composite potentiometer, volume control, tone control or rheostat with a switch, a casing, a resistance within the casing, a contact touching the resistance, means for moving the contact with respect to the resistance, a snap switch within the casing, connection between the contact and the switch adapted to throw the switch in one position of the contact, and a rotatable insulating partition carried by the contact moving means between the contact and the switch and movable with the contact, the edges of said partition extending closely adjacent the inner wall of the casing.

4. In a rheostat and switch unit, a cylindrical shell member, a base mounted in one end thereof, a resistance element on said base, a shaft journalled in said base and extending into said shell, a. disc carried by said shaft at its inner end and rotatable therewith, said disc completely closing the shell intermediate its ends, an end member in said shell opposite said base carrying a switch mechanism on its inner face, and means on said disc to actuate said switch mechanism.

ARTHUR M. DRAVING. WILLIAM IRWIN INGHAM. 

